Study on swelling of hydrogels (PAAm) at various temperatures by using fluorescence technique


Aktas D. , EVINGUER G. A. , PEKCAN O.

JOURNAL OF MATERIALS SCIENCE, vol.42, no.20, pp.8481-8488, 2007 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 42 Issue: 20
  • Publication Date: 2007
  • Doi Number: 10.1007/s10853-007-1764-x
  • Title of Journal : JOURNAL OF MATERIALS SCIENCE
  • Page Numbers: pp.8481-8488

Abstract

Steady-state fluorescence (SSF) technique was employed for studying swelling of polyacrylamide (PAAm) hydrogels. Disc-shaped gels were prepared by free-radical crosslinking copolymerization of acrylamide (AAm) with N, N'- methylenebis (acrylamide) (BIS) as crosslinker in the presence of ammonium persulfate (APS) as an initiator. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine was measured during in situ swelling process at various temperatures and it was observed that fluorescence intensity values decreased as swelling is proceeded. Li-Tanaka equation was used to determine the swelling time constants, tau(c) and cooperative diffusion coefficients, D-c from intensity, weight and volume variations during the swelling processes. It is observed that swelling time constants, tau(c) decreased and diffusion coefficients, D-c increased as the swelling temperature is increased. The swelling activation energies, Delta E were measured from the intensity, weight and volume variations and found to be 10.7, 32.2 and 64.1 kJ mol(-1), respectively.